About a week ago in this thread I speculated that the interchange at US 45 might be considered substandard for a new interstate, after someone mentioned an email from an MDOT official who seemed to suggest that some new but unspecified project might still be necessary to bring the road up to interstate standards. Well, I just drove through 78 @ 45 on my way to Tishomingo Park last weekend (blown away by that place! absolutely beautiful! had no idea there was anything like that in this state!!!).

I don't go through 78@45 often; it's been about 3 years since the last time. On this recent trip I was paying attention and looking for something that might be wrong. It seemed to me that those loop ramps were awfully tight for a junction like this, especially considering the proximity to the new Toyota plant. Could something like tight loops and the short weaving spaces that accompany them render the interchange substandard (assuming that unprotected full cloverleafs aren't themselves ruled out now, which is the theory I was working under before)?

Could an unmodified 78@45 hold up the final designation of this highway as I-22, or is this a non-issue?

About a week ago in this thread I speculated that the interchange at US 45 might be considered substandard for a new interstate, after someone mentioned an email from an MDOT official who seemed to suggest that some new but unspecified project might still be necessary to bring the road up to interstate standards. Well, I just drove through 78 @ 45 on my way to Tishomingo Park last weekend (blown away by that place! absolutely beautiful! had no idea there was anything like that in this state!!!).

I don't go through 78@45 often; it's been about 3 years since the last time. On this recent trip I was paying attention and looking for something that might be wrong. It seemed to me that those loop ramps were awfully tight for a junction like this, especially considering the proximity to the new Toyota plant. Could something like tight loops and the short weaving spaces that accompany them render the interchange substandard (assuming that unprotected full cloverleafs aren't themselves ruled out now, which is the theory I was working under before)?

Could an unmodified 78@45 hold up the final designation of this highway as I-22, or is this a non-issue?

Interstate qualifications are for mainline criteria, I believe. Tight loop ramps I don't think are sufficient to disqualify. Now, there could be substandard shoulders within the interchange area, or poor crowning, or substandard clearance, etc.

Loop radii don't matter, but acceleration/deceleration lanes and the angle at which the ramps enter/depart the mainline would matter. IIRC, the 45/78 intherchange has 20MPH loop ramps. But I don't remember how the loops interact with the 78 mainline.

Here is some Google Earth measurements from a few different cloverleaf/par-clo interchanges...

It's always difficult to gauge the size of those ramps from the road. I hadn't thought of using Google Earth to do it. Thanks for turning on the light for me.

From the responses you folks have posted, I gather that unprotected full cloverleaf interchanges are indeed still allowed on new interstates. That doesn't seem right to me. I think that CD lanes should be required at the least, and cloverstacks should be used more often.

Passed through the future interchange of Interstate 65 with Interstate 22 on Monday. Several pier supports are starting to rise and a good portion of the ramp from Interstate 65 north to Interstate 22 is taking shape. [click for larger images]

Work is 18.9% complete with 30% of the time elapsed, but the "slow" work is almost complete and completion is still anticipated to be around October 15, 2014. Also the 3000 foot related project to connect I-22 to U.S. 31 is anticipated to be let in June, with work expected to begin in August:http://blog.al.com/spotnews/2011/11/birminghams_corridor_x_interch.html

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Work on the interchange linking Corridor X and Interstate 65 --the largest road project in Birmingham-area history -- is expected to be completed by its original target date of Oct. 15, 2014, according to the Alabama Department of Transportation. The $168.6 million project began on Aug. 5, 2010. While 30 percent of the project's time frame has elapsed, the work was 18.9 percent complete as of last week. ALDOT division engineer Brian Davis said the first phase of the project required blasting away and removing rock before construction could begin. That work typically takes longer than the actual construction, Davis said. The blasting has to be done in daylight and when it's not raining. The explosive charges have to be strong enough to destroy rock, but weak enough to keep from damaging nearby buildings. "You know you're going to get behind (during blasting), but we're basically on schedule. We're almost to the items where you can get ahead," Davis said. In the coming weeks, columns protruding from the ground at the north Birmingham work site will begin looking more like bridges, Davis said. "It's like an assembly line," Davis said of the upcoming work that will add girders and bridge decking to those columns. "Once you get to that, it starts to look like a bridge." The finished project -- roughly 1.5 miles with 14 ramps and 14 bridges -- will all but complete Alabama's roughly 96-mile portion of the Birmingham-to-Memphis interstate that will be known as Interstate 22. The work, which is being performed by the Atlanta-based Archer Western, is the most expensive contract ALDOT has ever awarded, although past contracts might equal that amount if adjusted for inflation. Future phases will include building "collector/distributor roads" -- basically service roads -- that will divert traffic from I-65 to keep from disrupting traffic as workers rebuild that stretch of interstate. Davis said a date has not been set for when that work will be performed. The finished product will be a four-level, 85-foot-tall interchange that ALDOT officials have said will be similar to the I-459/65 interchange in Hoover. Bids will be invited in June for a related project that will build a 3,000-foot stretch of road linking I-22 to U.S. 31 in north Birmingham, with work expected to start in August, said ALDOT spokeswoman Linda Crockett. That work, which ALDOT has estimated will cost between $15 million and $20 million, should also be completed in 2014.

Here is a measurement for I-10 at US 49 in Gulfport. The I-10 eastbound weave section is around 625 feet, which I think is sufficient enough in light to moderate traffic. But that doesn't mean it's a good idea to use them. If MS really has the money, they should redo the interchange to make movements as easy as possible.

Here is a measurement for I-10 at US 49 in Gulfport. The I-10 eastbound weave section is around 625 feet, which I think is sufficient enough in light to moderate traffic. But that doesn't mean it's a good idea to use them. If MS really has the money, they should redo the interchange to make movements as easy as possible.

Here is a link to the Cambridge Systematics/TDOT study of the Lamar Corridor:http://www.tdot.state.tn.us/documents/LamarAvenueCorridor_June2011.pdfExtending I-22 along Lamar Avenue would provide the most traffic relief [page 8-12 of study; page 70/81 of pdf]:"Upgrading Lamar Avenue to an Interstate provides the most traffic relief benefits for Lamar Avenue. It reduces delay the most both for Lamar Avenue and for the study area as a whole. It also provides the lowest travel time for traveling the entire length of Lamar Avenue. It also provides a seamless connection to I-22, which has been constructed along the Lamar Avenue alignment in Mississippi."However, extending I-22 along Lamar Avenue would not provide the highest benefit/cost ratio [page 8-12 of study; page 70/81 of pdf]:"Adding lanes to Lamar Avenue provide the highest benefit/cost ratios for all of the Lamar Avenue improvements. This is because their costs are significantly lower than upgrading Lamar Avenue to an Interstate. Making Lamar Avenue eight lanes provides roughly two-thirds of the benefit of upgrading Lamar to an Interstate with only one-third of the cost. Making Lamar Avenue six lanes provides half the benefit with only one-sixth of the costs."

As much as I would like to see Lamar Ave upgraded to interstate standards, with the current budget climate, I don't think it will happen all at once or in it's entirety. What I would like to see is interchanges at the major intersections first (Holmes, Shelby, Winchester) along with a reconfiguration of the Getwell Rd interchange so that Lamar is the through route. Build the interchanges to interstate standards. Widen Lamar to at least six lanes through the interchanges. Build frontage roads on either end of the interchange to maintain local access. Then once the interchanges are upgraded, widen Lamar between the interchanges. As money becomes available, build frontage roads on either side of Lamar and close off access between the interchanges. Seems like that would be the best bang for the buck long-term.

http://blog.al.com/spotnews/2011/11/birminghams_corridor_x_interch.htmlWork on the interchange linking Corridor X and Interstate 65 --the largest road project in Birmingham-area history -- is expected to be completed by its original target date of Oct. 15, 2014, according to the Alabama Department of Transportation ... Bids will be invited in June for a related project that will build a 3,000-foot stretch of road linking I-22 to U.S. 31 in north Birmingham, with work expected to start in August, said ALDOT spokeswoman Linda Crockett. That work, which ALDOT has estimated will cost between $15 million and $20 million, should also be completed in 2014.

This article offers a ray of hope that the I-22/I-65 interchange project will be completed before October, 2014. The official estimate is still October, 2014, but an engineer from the third division personally believes it will be completed before then:

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Brian Davis, an engineer with ALDOT’s third division ... said ... Four resurfacing projects, totaling more than $14 million to re-pave nearly 14 miles of Corridor X, are scheduled to take place this summer.“These will be back-to-back-to-back-to-back projects on Corridor X,” Davis said ....Davis also said work on the final phase of I-22 should be completed by the Fall of 2014.“We are ahead of schedule and I think it will be completed sooner than that, but Fall of 2014 remains the current estimate,” he said.

I drove down to Birmingham today to check out the progress on the I-22/I-65 interchange. Work has been moving along at a steady rate.

One of the main reasons for me going is to scope out potential vantage points for a possible road meet this fall. I will post another thread in the Road Meet forum with details on that.

Here are some pictures I captured during the trip.

Looking along I-65 NB. Bridge construction adjacent to the NB lanes are for future lanes that will serve as both collector/distributor lanes and NB lanes. The current NB lanes will become the future SB lanes, and the current SB lanes will become the SB collector/distributor lanes. These bridges cross the Norfolk Southern railroad.

I-65 NB close to where the flyovers will "converge." The tall pier on the right will be the flyover from EB I-22 to NB I-65. Bridge construction adjacent to the roadway is for the lanes referred to above. These bridges will pass over I-22.

This view looks east from a dead-end street along I-22 towards the interchange with I-65. The ramp on the right will lead up to both I-65 north and south.

Closeup of the pier under construction from above:

Current end of grading for I-22 itself. Past the barricades it will bridge over the railroad and then pass underneath I-65.

Piers for the ramp from SB I-65 to WB I-22 that will pass over the railroad.

Looking from 47th Avenue North, the new bridge is now open to traffic on the right and the old one on the left is being demolished. A new bridge is necessary to accommodate the new lanes being built to the east of current I-65.

Looking south along what will be the future NB main lanes and collector/distributor lanes for I-65. This looks from the 47th Ave N overpass over I-65.

Grading for the ramp from I-65 SB to I-22 WB.

These signs will need to be relocated...

Looking south along I-65 from the 47th Avenue N overpass:

Closeup of the bent construction for the flyover from EB I-22 to NB I-65: